DINOSAURS OF THAILAND

This beautiful dinosaur track is from Kalasin Dinosaur Park in northeastern Thailand. 

Thailand boasts some of the finest Mesozoic trackways from five endemic dinosaur species.  

Since 1976, the Department of Mineral Resources with Thai-French Paleontological Project had continuously investigated the dinosaurs in the Phu Wiang mountains. The project found so many vertebrae, teeth, and footprints of the dinosaurs mainly from the sandstones of the Early Cretaceous Sao Khua Formation (about 130 million years old). These include sauropods and theropods ranging in size from adorable chickens to beasties up to 15 meters long. 

The Thai dinosaur record from the continental rocks of the Khorat Plateau is the best in Southeast Asia. The oldest footprints are those from small dinosaurs from the Middle to Late Jurassic Phra Wihan Formation. The most varied dinosaur assemblages come from the Late Jurassic Sao Khua Formation. Here we see the sauropods dominate the fossil beds interspersed with a variety of theropods. Large theropod footprints are known from the Early Cretaceous Phu Phan Formation. Theropods and the primitive ceratopsian Psittacosaurus occur in the Aptian-Albian Khok Kruat Formation. We find dinosaur material further north along the Mekong River region of Laos. Thai fossils show a close relationship to those found in China and Mongolia. 

If you'd like to go visit them, there is a rather nice display at the Phu Wiang Dinosaur Museum in the newly established Wiang Kao district about 80 kilometres to the west of the provincial capital of Khon Kaen. They have several species on display, including: Phuwiangosaurus sirindhornae, Siamosaurus suteethorni, Siamotyrannus isanensis, Kinnareemimus khonkaenensis, Compsognathus (awe, a wee vicious chicken...) and, of course, the Phu Wiang dinosaur footprints.

If you'd like to visit Kalasin Dinosaur Park, follow route 227 towards Lam Pao Dam and Dok Ket Beach. Instead of turning left towards the dam, continue up towards Sirindhorn Dinosaur Museum. You'll see it on your left about 5km before the museum. For some GPS help, pop this into Google Maps: Dinosaur Park, Ni Khom, Sahatsakhan District, Kalasin 46140, Thailand.

References: 

• Ingavat, R., Janvier, R., and Taquet, P. (1978) Decouverte en Thailande d'une portion de femur de dinosaure sauropode (Saurischia, Reptilia). C.R. Soc.Geol.France 3: 140-141
• Wickanet Songtham and Benja Sektheera (2006) Phuwiangosaurus sirindhornae Bangkok: Department of Mineral Resources: 100 pages
• Buffetaut, E., Suteethorn, V., and Tong, H. (2009) An earliest 'ostrich dinosaur' (Theropoda: Ornithomosauria) from the Early Cretaceous Sao Khua Formation of NE Thailand, pp. 229-243, in E. Buffetaut, G. Cuny, J. Le Loeuff, and V. Suteethorn (eds.), Late Palaeozoic and Mesozoic Ecosystem in SE Asia. Geological Society, London, Special Publication 315.

SPLIT SAIL SPINOSAURID

Back in the Cretaceous in what is now the heart of the Indochinese Peninsula, a group of mighty spinosaur with an unusual split sail were playing and hunting in the local waters. 

Picture an alligator whose legs grew especially long, add a big split sail on his back and arms that could grasp. That's kind of what these big therapod dinosaurs looked like.

The first fossil remains of Ichthyovenator were found in 2010 at Ban Kalum in the Grès Supérieurs Formation of the Savannakhet Basin in Savannakhet Province in the province of Laos. We have found other fossil remains at the site including fossil fish, iguanodontians and some compelling sauropod and ornithopod tracks.

Dinosaur remains are among the fossils that have been recovered from the formation. It is equivalent to the Khok Kruat Formation of northeastern Thailand, a fluvial formation similar in age. 

The Khok Kruat Formation is a treasure trove of fossil goodies as well. We have found the remains of fossil sharks, fish, turtles, crocodilians and pterosaurs. Phuwiangosaurus-like teeth, Siamosaurus teeth, and fragmentary postcranial remains of spinosaurids have been dug up there. We have also found Fukuiraptor-like teeth—and, being close in age, they are both Albian, it is likely just a matter of time before we find Ichthyovenator bones there as well.

Ichthyovenator had a long, shallow snout and robust forelimbs. Its diet likely mainly consisted of aquatic prey, hence its etymology. Spinosaurids are also known to have eaten small dinosaurs and pterosaurs in addition to fish. 

Ichthyovenator's conspicuous split sail might have been used for sexual display or species recognition. Fossil evidence suggests spinosaurids, especially spinosaurines, were adapted for semiaquatic lifestyles. The vertebral spines of Ichthyovenator's tail were unusually tall, suggesting—as in today's crocodilians—the tail may have aided in swimming. Ichthyovenator lived alongside sauropod and ornithopod dinosaurs, as well as bivalves, fish and turtles.

These fossilized bones were recovered from a red sandstone layer within a surface area of less than 2 square metres (22 sq ft). 

So, what did we find? So many great bits and pieces of these giant beasts as a massive jigsaw puzzle. Gathered together, they have been designated under the specimen numbers MDS BK10-01 to 15. There is a partly articulated, well-preserved skeleton. Sadly, missing are the skull and limbs. In with the bits and pieces were the third-to-last dorsal (back) vertebra, the neural spine of the last dorsal vertebra, five partial sacral (hip) vertebrae, the first two caudal (tail) vertebrae, both ilia (main hip bones), a right pubis (pubic bone), both ischia (lower and rearmost hip bones) and a posterior dorsal rib. 

The twelfth dorsal spine is bent sideways when viewed front-to-back due to taphonomic distortion. The central (vertebral bodies) of the sacrals are largely incomplete due to erosion but preserved all of their accompanying spines with their upper edges intact. 

At the time of Ichthyovenator's description, excavations at the site were still ongoing. Cast fossil spinal column laid out inside a glass display case at a museum Casts of the vertebrae at the Muséum National d'Histoire Naturelle, Paris After undergoing preparation in 2011, the skeleton was used as the basis, or holotype, for the type species Ichthyovenator laosensis, which was named and described in 2012 by palaeontologists Ronan Allain, Tiengkham Xeisanavong, Philippe Richir, and Bounsou Khentavong. 

The generic name is derived from the Old Greek word ἰχθύς (ichthys), "fish", and the Latin word venator, "hunter", in reference to its likely piscivorous or fish-eating lifestyle. The specific name refers to its provenance in Laos.

Ichthyovenator is the third named spinosaurid dinosaur from Asia after the Thai genus Siamosaurus in 1986 and the Chinese species "Sinopliosaurus" fusuiensis in 2009. The latter may represent the same animal as Siamosaurus. 

In 2014, Allain published a conference paper on Ichthyovenator; the abstract indicated additional remains from the original individual had been found after excavations continued in 2012. These remains include three teeth, the left pubis, and many vertebrae, including a nearly complete neck, the first dorsal vertebra, and seven more caudal vertebrae.

Some of these additional vertebrae were compared with those of other spinosaurids in a 2015 paper by German palaeontologist Serjoscha Evers and colleagues, in which they noted similarities with the vertebrae of the African spinosaurid Sigilmassasaurus. 

Allain and his team considered Ichthyovenator as representing the first unequivocal spinosaurid from Asia. Though prior spinosaurids had been named from the continent—including Siamosaurus from Thailand's Barremian Sao Khua Formation and "Sinopliosaurus" fusuiensis from China's Aptian Xinlong Formation—the authors noted that palaeontologists have debated the validity of these taxa because they are only confidently known from isolated teeth. 

Brazilian palaeontologists Marcos Sales and Caesar Schultz have suggested these teeth may eventually be attributed to spinosaurids similar to Ichthyovenator. In addition to tooth fossils, a spinosaurid skeleton that possibly belongs to Siamosaurus was excavated from the Thai Khok Kruat Formation in 2004 and was identified as a definite spinosaur in a 2008 conference abstract by Angela Milner and colleagues, eight years before Ichthyovenator's description.